[PATCH v4 0/4] Teach phylib hard-resetting devices

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Revision v4 of 2 in this series.

13 messages, 6 authors, 2017-12-11 · open the first message on its own page

[PATCH v4 0/4] Teach phylib hard-resetting devices

From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: 2017-12-04 10:35:20 

	Hi David, Andrew, Florian, Simon, Magnus,

This patch series adds optional PHY reset support to phylib.

The first two patches are destined for David's net-next tree. They add
core PHY reset code, and update a driver that currently uses its own
reset code.

The last two patches are destined for Simon's renesas tree.  They add
properties to describe the EthernetAVB PHY reset topology to the common
Salvator-X/XS and ULCB DTS files, which solves two issues:
  1. On Salvator-XS, the enable pin of the regulator providing PHY power
     is connected to PRESETn, and PSCI powers down the SoC during system
     suspend.  Hence a PHY reset is needed to restore network
     functionality after system resume.
  2. Linux should not rely on the boot loader having reset the PHY, but
     should reset the PHY during driver probe.

Changes compared to v3:
  - Remove Florian's Acked-by,
  - Add missing #include <linux/gpio/consumer.h>,
  - Re-add the gpiod check, as the dummy gpiod_set_value() for !GPIOLIB
    does not ignore NULL, and calls WARN_ON(1),
  - Do not reassert the reset signal if {mdio,phy}_probe() or
    phy_device_register() succeeded, as that may destroy initial setup,
  - Do not deassert the reset signal in {mdio,phy}_remove(), as it
    should already be deasserted,
  - Bring the PHY back into reset state in phy_device_remove(),
  - Move/consolidate GPIO descriptor acquiring code from
    of_mdiobus_register_phy() and of_mdiobus_register_device() to
    mdiobus_register_device().
    Note that this changes behavior slightly, in that the reset signal
    is now also asserted when called from of_mdiobus_register_device().
  - Add Reviewed-by,

Changes compared to v2, as sent by Sergei Shtylyov:
  - Fix fwnode_get_named_gpiod() call due to added parameters (which
    allowed to eliminate the gpiod_direction_output() call),
  - Rebased, refreshed, reworded,
  - Take over from Sergei,
  - Add Acked-by,
  - Remove unneeded gpiod check, as gpiod_set_value() handles NULL fine,
  - Handle fwnode_get_named_gpiod() errors correctly:
      - -ENOENT is ignored (the GPIO is optional), and turned into NULL,
	which allowed to remove all later !IS_ERR() checks,
      - Other errors (incl. -EPROBE_DEFER) are propagated,
  - Extract DTS patches from series "[PATCH 0/4] ravb: Add PHY reset
    support" (https://www.spinics.net/lists/netdev/msg457308.html), and
    incorporate in this series, after moving reset-gpios from the
    ethernet to the ethernet-phy node.

Given (1) the new reset-gpios DT property in the PHY node follows
established practises, (2) the DT binding change in the first patch has
been acked by Rob, and (3) the DTS patch does not cause any regressions
if it is applied before the PHY driver patches, the DTS patches can be
applied independently.

Thanks!

Geert Uytterhoeven (2):
  arm64: dts: renesas: salvator-common: Add EthernetAVB PHY reset
  arm64: dts: renesas: ulcb: Add EthernetAVB PHY reset

Sergei Shtylyov (2):
  phylib: Add device reset GPIO support
  macb: Kill PHY reset code

 Documentation/devicetree/bindings/net/phy.txt    |  2 ++
 arch/arm64/boot/dts/renesas/salvator-common.dtsi |  1 +
 arch/arm64/boot/dts/renesas/ulcb.dtsi            |  1 +
 drivers/net/ethernet/cadence/macb.h              |  1 -
 drivers/net/ethernet/cadence/macb_main.c         | 21 ----------------
 drivers/net/phy/at803x.c                         | 18 +++----------
 drivers/net/phy/mdio_bus.c                       | 21 ++++++++++++++++
 drivers/net/phy/mdio_device.c                    | 25 ++++++++++++++++--
 drivers/net/phy/phy_device.c                     | 32 ++++++++++++++++++++++--
 include/linux/mdio.h                             |  3 +++
 include/linux/phy.h                              |  5 ++++
 11 files changed, 89 insertions(+), 41 deletions(-)

-- 
2.7.4

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

[PATCH v4 3/4] arm64: dts: renesas: salvator-common: Add EthernetAVB PHY reset

From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: 2017-12-04 10:35:10 

Describe the GPIO used to reset the Ethernet PHY for EthernetAVB.
This allows the driver to reset the PHY during probe and after system
resume.

This fixes Ethernet operation after resume from s2ram on Salvator-XS,
where the enable pin of the regulator providing PHY power is connected
to PRESETn, and PSCI powers down the SoC during system suspend.

On Salvator-X, the enable pin is always pulled high, but the driver may
still need to reset the PHY if this wasn't done by the bootloader
before.

Inspired by patches in the BSP for the individual Salvator-X/XS boards
by Kazuya Mizuguchi.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
For proper PHY reset operation during system resume, this depends on
"[PATCH v4 1/4] phylib: Add device reset GPIO support".
However, this patch can be applied independently.

v4:
  - No changes,

v3:
  - Extract from series "[PATCH 0/4] ravb: Add PHY reset support", and
    incorporate in this series,
  - Move reset-gpios from the ethernet to the ethernet-phy node.
---
 arch/arm64/boot/dts/renesas/salvator-common.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/boot/dts/renesas/salvator-common.dtsi b/arch/arm64/boot/dts/renesas/salvator-common.dtsi
index a298df74ca6c037f..6a9524ff881306cf 100644
--- a/arch/arm64/boot/dts/renesas/salvator-common.dtsi
+++ b/arch/arm64/boot/dts/renesas/salvator-common.dtsi
@@ -264,6 +264,7 @@
 		reg = <0>;
 		interrupt-parent = <&gpio2>;
 		interrupts = <11 IRQ_TYPE_LEVEL_LOW>;
+		reset-gpios = <&gpio2 10 GPIO_ACTIVE_LOW>;
 	};
 };
 
-- 
2.7.4

[PATCH v4 2/4] macb: Kill PHY reset code

From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: 2017-12-04 10:35:15 

From: Sergei Shtylyov <redacted>

With the phylib now being aware of the "reset-gpios" PHY node property,
there should be no need to frob the PHY reset in this driver anymore...

Signed-off-by: Sergei Shtylyov <redacted>
Acked-by: Nicolas Ferre <redacted>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v4:
  - Add Reviewed-by,

v3:
  - Resolve rejects due to the file being renamed, refresh the patch,
  - Add code to reset PHY on probe error,
  - Edit patch description,
  - Take over from Sergei,
  - Add Acked-by,

v2:
  - No changes.
---
 drivers/net/ethernet/cadence/macb.h      |  1 -
 drivers/net/ethernet/cadence/macb_main.c | 21 ---------------------
 2 files changed, 22 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index 3165c2ba58f97744..c50c5ec49b1dc585 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -1171,7 +1171,6 @@ struct macb {
 	unsigned int		dma_burst_length;
 
 	phy_interface_t		phy_interface;
-	struct gpio_desc	*reset_gpio;
 
 	/* AT91RM9200 transmit */
 	struct sk_buff *skb;			/* holds skb until xmit interrupt completes */
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index c5fa87cdc6c401a7..3f0dfb20fdbcf936 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -3803,7 +3803,6 @@ static int macb_probe(struct platform_device *pdev)
 					      = macb_config->clk_init;
 	int (*init)(struct platform_device *) = macb_config->init;
 	struct device_node *np = pdev->dev.of_node;
-	struct device_node *phy_node;
 	struct clk *pclk, *hclk = NULL, *tx_clk = NULL, *rx_clk = NULL;
 	unsigned int queue_mask, num_queues;
 	struct macb_platform_data *pdata;
@@ -3909,18 +3908,6 @@ static int macb_probe(struct platform_device *pdev)
 	else
 		macb_get_hwaddr(bp);
 
-	/* Power up the PHY if there is a GPIO reset */
-	phy_node =  of_get_next_available_child(np, NULL);
-	if (phy_node) {
-		int gpio = of_get_named_gpio(phy_node, "reset-gpios", 0);
-
-		if (gpio_is_valid(gpio)) {
-			bp->reset_gpio = gpio_to_desc(gpio);
-			gpiod_direction_output(bp->reset_gpio, 1);
-		}
-	}
-	of_node_put(phy_node);
-
 	err = of_get_phy_mode(np);
 	if (err < 0) {
 		pdata = dev_get_platdata(&pdev->dev);
@@ -3967,10 +3954,6 @@ static int macb_probe(struct platform_device *pdev)
 		of_phy_deregister_fixed_link(np);
 	mdiobus_free(bp->mii_bus);
 
-	/* Shutdown the PHY if there is a GPIO reset */
-	if (bp->reset_gpio)
-		gpiod_set_value(bp->reset_gpio, 0);
-
 err_out_free_netdev:
 	free_netdev(dev);
 
@@ -4001,10 +3984,6 @@ static int macb_remove(struct platform_device *pdev)
 		dev->phydev = NULL;
 		mdiobus_free(bp->mii_bus);
 
-		/* Shutdown the PHY if there is a GPIO reset */
-		if (bp->reset_gpio)
-			gpiod_set_value(bp->reset_gpio, 0);
-
 		unregister_netdev(dev);
 		clk_disable_unprepare(bp->tx_clk);
 		clk_disable_unprepare(bp->hclk);
-- 
2.7.4

[PATCH v4 4/4] arm64: dts: renesas: ulcb: Add EthernetAVB PHY reset

From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: 2017-12-04 10:35:17 

Describe the GPIO used to reset the Ethernet PHY for EthernetAVB.
This allows the driver to reset the PHY during probe and after system
resume.

On ULCB, the enable pin of the regulator providing PHY power is always
pulled high, but the driver may still need to reset the PHY if this
wasn't done by the bootloader before.

Inspired by patches in the BSP for the individual Salvator-X/XS boards
by Kazuya Mizuguchi.

Signed-off-by: Geert Uytterhoeven <redacted>
---
Compile-tested only.

v4:
  - No changes,

v3:
  - Extract from series "[PATCH 0/4] ravb: Add PHY reset support", and
    incorporate in this series,
  - Move reset-gpios from the ethernet to the ethernet-phy node.
---
 arch/arm64/boot/dts/renesas/ulcb.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/boot/dts/renesas/ulcb.dtsi b/arch/arm64/boot/dts/renesas/ulcb.dtsi
index 0d85b315ce711c8f..be91016e0b48f196 100644
--- a/arch/arm64/boot/dts/renesas/ulcb.dtsi
+++ b/arch/arm64/boot/dts/renesas/ulcb.dtsi
@@ -154,6 +154,7 @@
 		reg = <0>;
 		interrupt-parent = <&gpio2>;
 		interrupts = <11 IRQ_TYPE_LEVEL_LOW>;
+		reset-gpios = <&gpio2 10 GPIO_ACTIVE_LOW>;
 	};
 };
 
-- 
2.7.4

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[PATCH v4 1/4] phylib: Add device reset GPIO support

From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: 2017-12-04 10:36:58 

From: Sergei Shtylyov <redacted>

The PHY devices sometimes do have their reset signal (maybe even power
supply?) tied to some GPIO and sometimes it also does happen that a boot
loader does not leave it deasserted. So far this issue has been attacked
from (as I believe) a wrong angle: by teaching the MAC driver to manipulate
the GPIO in question; that solution, when applied to the device trees, led
to adding the PHY reset GPIO properties to the MAC device node, with one
exception: Cadence MACB driver which could handle the "reset-gpios" prop
in a PHY device subnode. I believe that the correct approach is to teach
the 'phylib' to get the MDIO device reset GPIO from the device tree node
corresponding to this device -- which this patch is doing...

Note that I had to modify the AT803x PHY driver as it would stop working
otherwise -- it made use of the reset GPIO for its own purposes...

Signed-off-by: Sergei Shtylyov <redacted>
Acked-by: Rob Herring <robh@kernel.org>
[geert: Propagate actual errors from fwnode_get_named_gpiod()]
[geert: Avoid destroying initial setup]
[geert: Consolidate GPIO descriptor acquiring code]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v4:
  - Remove Florian's Acked-by,
  - Add missing #include <linux/gpio/consumer.h>,
  - Re-add the gpiod check, as the dummy gpiod_set_value() for !GPIOLIB
    does not ignore NULL, and calls WARN_ON(1),
  - Do not reassert the reset signal if {mdio,phy}_probe() or
    phy_device_register() succeeded, as that may destroy initial setup,
  - Do not deassert the reset signal in {mdio,phy}_remove(), as it
    should already be deasserted,
  - Bring the PHY back into reset state in phy_device_remove(),
  - Move/consolidate GPIO descriptor acquiring code from
    of_mdiobus_register_phy() and of_mdiobus_register_device() to
    mdiobus_register_device().
    Note that this changes behavior slightly, in that the reset signal
    is now also asserted when called from of_mdiobus_register_device().

v3:
  - Fix fwnode_get_named_gpiod() call due to added parameters (which
    allowed to eliminate the gpiod_direction_output() call),
  - Undelete one blank line in the AT803x driver,
  - Resolve rejects, refresh patch,
  - Reword/reformat changelog,
  - Take over from Sergei,
  - Add Acked-by,
  - Remove unneeded gpiod check, as gpiod_set_value() handles NULL fine,
  - Handle fwnode_get_named_gpiod() errors correctly:
      - -ENOENT is ignored (the GPIO is optional), and turned into NULL,
	which allowed to remove all later !IS_ERR() checks,
      - Other errors (incl. -EPROBE_DEFER) are propagated [*],

v2:
  - Reformat changelog,
  - Resolve rejects, refresh patch.
---
 Documentation/devicetree/bindings/net/phy.txt |  2 ++
 drivers/net/phy/at803x.c                      | 18 +++------------
 drivers/net/phy/mdio_bus.c                    | 21 ++++++++++++++++++
 drivers/net/phy/mdio_device.c                 | 25 +++++++++++++++++++--
 drivers/net/phy/phy_device.c                  | 32 +++++++++++++++++++++++++--
 include/linux/mdio.h                          |  3 +++
 include/linux/phy.h                           |  5 +++++
 7 files changed, 87 insertions(+), 19 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt
index 77d0b2a61ffa96fc..c05479f5ac7cc837 100644
--- a/Documentation/devicetree/bindings/net/phy.txt
+++ b/Documentation/devicetree/bindings/net/phy.txt
@@ -53,6 +53,8 @@ Optional Properties:
   to ensure the integrated PHY is used. The absence of this property indicates
   the muxers should be configured so that the external PHY is used.
 
+- reset-gpios: The GPIO phandle and specifier for the PHY reset signal.
+
 Example:
 
 ethernet-phy@0 {
diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
index de7dd6566df7a364..29da7a3c7a3761c0 100644
--- a/drivers/net/phy/at803x.c
+++ b/drivers/net/phy/at803x.c
@@ -71,7 +71,6 @@ MODULE_LICENSE("GPL");
 
 struct at803x_priv {
 	bool phy_reset:1;
-	struct gpio_desc *gpiod_reset;
 };
 
 struct at803x_context {
@@ -254,22 +253,11 @@ static int at803x_probe(struct phy_device *phydev)
 {
 	struct device *dev = &phydev->mdio.dev;
 	struct at803x_priv *priv;
-	struct gpio_desc *gpiod_reset;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
-	if (phydev->drv->phy_id != ATH8030_PHY_ID)
-		goto does_not_require_reset_workaround;
-
-	gpiod_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
-	if (IS_ERR(gpiod_reset))
-		return PTR_ERR(gpiod_reset);
-
-	priv->gpiod_reset = gpiod_reset;
-
-does_not_require_reset_workaround:
 	phydev->priv = priv;
 
 	return 0;
@@ -343,14 +331,14 @@ static void at803x_link_change_notify(struct phy_device *phydev)
 	 * cannot recover from by software.
 	 */
 	if (phydev->state == PHY_NOLINK) {
-		if (priv->gpiod_reset && !priv->phy_reset) {
+		if (phydev->mdio.reset && !priv->phy_reset) {
 			struct at803x_context context;
 
 			at803x_context_save(phydev, &context);
 
-			gpiod_set_value(priv->gpiod_reset, 1);
+			phy_device_reset(phydev, 1);
 			msleep(1);
-			gpiod_set_value(priv->gpiod_reset, 0);
+			phy_device_reset(phydev, 0);
 			msleep(1);
 
 			at803x_context_restore(phydev, &context);
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 2df7b62c1a36811e..c97d55cd6679412e 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -38,6 +38,7 @@
 #include <linux/phy.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>
+#include <linux/gpio/consumer.h>
 
 #include <asm/irq.h>
 
@@ -48,9 +49,26 @@
 
 int mdiobus_register_device(struct mdio_device *mdiodev)
 {
+	struct gpio_desc *gpiod;
+
 	if (mdiodev->bus->mdio_map[mdiodev->addr])
 		return -EBUSY;
 
+	/* Deassert the optional reset signal */
+	if (mdiodev->dev.of_node)
+		gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
+					       "reset-gpios", 0, GPIOD_OUT_LOW,
+					       "PHY reset");
+	if (PTR_ERR(gpiod) == -ENOENT)
+		gpiod = NULL;
+	else if (IS_ERR(gpiod))
+		return PTR_ERR(gpiod);
+
+	mdiodev->reset = gpiod;
+
+	/* Assert the reset signal again */
+	mdio_device_reset(mdiodev, 1);
+
 	mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
 
 	return 0;
@@ -420,6 +438,9 @@ void mdiobus_unregister(struct mii_bus *bus)
 		if (!mdiodev)
 			continue;
 
+		if (mdiodev->reset)
+			gpiod_put(mdiodev->reset);
+
 		mdiodev->device_remove(mdiodev);
 		mdiodev->device_free(mdiodev);
 	}
diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c
index e24f28924af8953d..75d97dd9fb281704 100644
--- a/drivers/net/phy/mdio_device.c
+++ b/drivers/net/phy/mdio_device.c
@@ -12,6 +12,8 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/errno.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -114,6 +116,13 @@ void mdio_device_remove(struct mdio_device *mdiodev)
 }
 EXPORT_SYMBOL(mdio_device_remove);
 
+void mdio_device_reset(struct mdio_device *mdiodev, int value)
+{
+	if (mdiodev->reset)
+		gpiod_set_value(mdiodev->reset, value);
+}
+EXPORT_SYMBOL(mdio_device_reset);
+
 /**
  * mdio_probe - probe an MDIO device
  * @dev: device to probe
@@ -128,8 +137,16 @@ static int mdio_probe(struct device *dev)
 	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
 	int err = 0;
 
-	if (mdiodrv->probe)
+	if (mdiodrv->probe) {
+		/* Deassert the reset signal */
+		mdio_device_reset(mdiodev, 0);
+
 		err = mdiodrv->probe(mdiodev);
+		if (err) {
+			/* Assert the reset signal */
+			mdio_device_reset(mdiodev, 1);
+		}
+	}
 
 	return err;
 }
@@ -140,9 +157,13 @@ static int mdio_remove(struct device *dev)
 	struct device_driver *drv = mdiodev->dev.driver;
 	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
 
-	if (mdiodrv->remove)
+	if (mdiodrv->remove) {
 		mdiodrv->remove(mdiodev);
 
+		/* Assert the reset signal */
+		mdio_device_reset(mdiodev, 1);
+	}
+
 	return 0;
 }
 
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 8154fb706751e8ad..1de5e242b8b4cda3 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -632,6 +632,9 @@ int phy_device_register(struct phy_device *phydev)
 	if (err)
 		return err;
 
+	/* Deassert the reset signal */
+	phy_device_reset(phydev, 0);
+
 	/* Run all of the fixups for this PHY */
 	err = phy_scan_fixups(phydev);
 	if (err) {
@@ -650,6 +653,9 @@ int phy_device_register(struct phy_device *phydev)
 	return 0;
 
  out:
+	/* Assert the reset signal */
+	phy_device_reset(phydev, 1);
+
 	mdiobus_unregister_device(&phydev->mdio);
 	return err;
 }
@@ -666,6 +672,10 @@ EXPORT_SYMBOL(phy_device_register);
 void phy_device_remove(struct phy_device *phydev)
 {
 	device_del(&phydev->mdio.dev);
+
+	/* Assert the reset signal */
+	phy_device_reset(phydev, 1);
+
 	mdiobus_unregister_device(&phydev->mdio);
 }
 EXPORT_SYMBOL(phy_device_remove);
@@ -849,6 +859,9 @@ int phy_init_hw(struct phy_device *phydev)
 {
 	int ret = 0;
 
+	/* Deassert the reset signal */
+	phy_device_reset(phydev, 0);
+
 	if (!phydev->drv || !phydev->drv->config_init)
 		return 0;
 
@@ -1126,6 +1139,9 @@ void phy_detach(struct phy_device *phydev)
 	put_device(&phydev->mdio.dev);
 	if (ndev_owner != bus->owner)
 		module_put(bus->owner);
+
+	/* Assert the reset signal */
+	phy_device_reset(phydev, 1);
 }
 EXPORT_SYMBOL(phy_detach);
 
@@ -1811,8 +1827,16 @@ static int phy_probe(struct device *dev)
 	/* Set the state to READY by default */
 	phydev->state = PHY_READY;
 
-	if (phydev->drv->probe)
+	if (phydev->drv->probe) {
+		/* Deassert the reset signal */
+		phy_device_reset(phydev, 0);
+
 		err = phydev->drv->probe(phydev);
+		if (err) {
+			/* Assert the reset signal */
+			phy_device_reset(phydev, 1);
+		}
+	}
 
 	mutex_unlock(&phydev->lock);
 
@@ -1829,8 +1853,12 @@ static int phy_remove(struct device *dev)
 	phydev->state = PHY_DOWN;
 	mutex_unlock(&phydev->lock);
 
-	if (phydev->drv && phydev->drv->remove)
+	if (phydev->drv && phydev->drv->remove) {
 		phydev->drv->remove(phydev);
+
+		/* Assert the reset signal */
+		phy_device_reset(phydev, 1);
+	}
 	phydev->drv = NULL;
 
 	return 0;
diff --git a/include/linux/mdio.h b/include/linux/mdio.h
index ca08ab16ecdc9b78..92d4e55ffe675637 100644
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -12,6 +12,7 @@
 #include <uapi/linux/mdio.h>
 #include <linux/mod_devicetable.h>
 
+struct gpio_desc;
 struct mii_bus;
 
 /* Multiple levels of nesting are possible. However typically this is
@@ -39,6 +40,7 @@ struct mdio_device {
 	/* Bus address of the MDIO device (0-31) */
 	int addr;
 	int flags;
+	struct gpio_desc *reset;
 };
 #define to_mdio_device(d) container_of(d, struct mdio_device, dev)
 
@@ -71,6 +73,7 @@ void mdio_device_free(struct mdio_device *mdiodev);
 struct mdio_device *mdio_device_create(struct mii_bus *bus, int addr);
 int mdio_device_register(struct mdio_device *mdiodev);
 void mdio_device_remove(struct mdio_device *mdiodev);
+void mdio_device_reset(struct mdio_device *mdiodev, int value);
 int mdio_driver_register(struct mdio_driver *drv);
 void mdio_driver_unregister(struct mdio_driver *drv);
 int mdio_device_bus_match(struct device *dev, struct device_driver *drv);
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 4962af37722ac2ea..6106ed915841c97e 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -841,6 +841,11 @@ int phy_aneg_done(struct phy_device *phydev);
 int phy_stop_interrupts(struct phy_device *phydev);
 int phy_restart_aneg(struct phy_device *phydev);
 
+static inline void phy_device_reset(struct phy_device *phydev, int value)
+{
+	mdio_device_reset(&phydev->mdio, value);
+}
+
 #define phydev_err(_phydev, format, args...)	\
 	dev_err(&_phydev->mdio.dev, format, ##args)
 
-- 
2.7.4

[PATCH v4.1] phylib: Add device reset GPIO support

From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: 2017-12-04 12:35:22 

From: Sergei Shtylyov <redacted>

The PHY devices sometimes do have their reset signal (maybe even power
supply?) tied to some GPIO and sometimes it also does happen that a boot
loader does not leave it deasserted. So far this issue has been attacked
from (as I believe) a wrong angle: by teaching the MAC driver to manipulate
the GPIO in question; that solution, when applied to the device trees, led
to adding the PHY reset GPIO properties to the MAC device node, with one
exception: Cadence MACB driver which could handle the "reset-gpios" prop
in a PHY device subnode. I believe that the correct approach is to teach
the 'phylib' to get the MDIO device reset GPIO from the device tree node
corresponding to this device -- which this patch is doing...

Note that I had to modify the AT803x PHY driver as it would stop working
otherwise -- it made use of the reset GPIO for its own purposes...

Signed-off-by: Sergei Shtylyov <redacted>
Acked-by: Rob Herring <robh@kernel.org>
[geert: Propagate actual errors from fwnode_get_named_gpiod()]
[geert: Avoid destroying initial setup]
[geert: Consolidate GPIO descriptor acquiring code]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v4.1:
  - Fix uninitialized variable in mdiobus_register_device(),

v4:
  - Remove Florian's Acked-by,
  - Add missing #include <linux/gpio/consumer.h>,
  - Re-add the gpiod check, as the dummy gpiod_set_value() for !GPIOLIB
    does not ignore NULL, and calls WARN_ON(1),
  - Do not reassert the reset signal if {mdio,phy}_probe() or
    phy_device_register() succeeded, as that may destroy initial setup,
  - Do not deassert the reset signal in {mdio,phy}_remove(), as it
    should already be deasserted,
  - Bring the PHY back into reset state in phy_device_remove(),
  - Move/consolidate GPIO descriptor acquiring code from
    of_mdiobus_register_phy() and of_mdiobus_register_device() to
    mdiobus_register_device().
    Note that this changes behavior slightly, in that the reset signal
    is now also asserted when called from of_mdiobus_register_device().

v3:
  - Fix fwnode_get_named_gpiod() call due to added parameters (which
    allowed to eliminate the gpiod_direction_output() call),
  - Undelete one blank line in the AT803x driver,
  - Resolve rejects, refresh patch,
  - Reword/reformat changelog,
  - Take over from Sergei,
  - Add Acked-by,
  - Remove unneeded gpiod check, as gpiod_set_value() handles NULL fine,
  - Handle fwnode_get_named_gpiod() errors correctly:
      - -ENOENT is ignored (the GPIO is optional), and turned into NULL,
        which allowed to remove all later !IS_ERR() checks,
      - Other errors (incl. -EPROBE_DEFER) are propagated [*],

v2:
  - Reformat changelog,
  - Resolve rejects, refresh patch.
---
 Documentation/devicetree/bindings/net/phy.txt |  2 ++
 drivers/net/phy/at803x.c                      | 18 +++------------
 drivers/net/phy/mdio_bus.c                    | 21 ++++++++++++++++++
 drivers/net/phy/mdio_device.c                 | 25 +++++++++++++++++++--
 drivers/net/phy/phy_device.c                  | 32 +++++++++++++++++++++++++--
 include/linux/mdio.h                          |  3 +++
 include/linux/phy.h                           |  5 +++++
 7 files changed, 87 insertions(+), 19 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt
index 77d0b2a61ffa96fc..c05479f5ac7cc837 100644
--- a/Documentation/devicetree/bindings/net/phy.txt
+++ b/Documentation/devicetree/bindings/net/phy.txt
@@ -53,6 +53,8 @@ Optional Properties:
   to ensure the integrated PHY is used. The absence of this property indicates
   the muxers should be configured so that the external PHY is used.
 
+- reset-gpios: The GPIO phandle and specifier for the PHY reset signal.
+
 Example:
 
 ethernet-phy@0 {
diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
index de7dd6566df7a364..29da7a3c7a3761c0 100644
--- a/drivers/net/phy/at803x.c
+++ b/drivers/net/phy/at803x.c
@@ -71,7 +71,6 @@ MODULE_LICENSE("GPL");
 
 struct at803x_priv {
 	bool phy_reset:1;
-	struct gpio_desc *gpiod_reset;
 };
 
 struct at803x_context {
@@ -254,22 +253,11 @@ static int at803x_probe(struct phy_device *phydev)
 {
 	struct device *dev = &phydev->mdio.dev;
 	struct at803x_priv *priv;
-	struct gpio_desc *gpiod_reset;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
-	if (phydev->drv->phy_id != ATH8030_PHY_ID)
-		goto does_not_require_reset_workaround;
-
-	gpiod_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
-	if (IS_ERR(gpiod_reset))
-		return PTR_ERR(gpiod_reset);
-
-	priv->gpiod_reset = gpiod_reset;
-
-does_not_require_reset_workaround:
 	phydev->priv = priv;
 
 	return 0;
@@ -343,14 +331,14 @@ static void at803x_link_change_notify(struct phy_device *phydev)
 	 * cannot recover from by software.
 	 */
 	if (phydev->state == PHY_NOLINK) {
-		if (priv->gpiod_reset && !priv->phy_reset) {
+		if (phydev->mdio.reset && !priv->phy_reset) {
 			struct at803x_context context;
 
 			at803x_context_save(phydev, &context);
 
-			gpiod_set_value(priv->gpiod_reset, 1);
+			phy_device_reset(phydev, 1);
 			msleep(1);
-			gpiod_set_value(priv->gpiod_reset, 0);
+			phy_device_reset(phydev, 0);
 			msleep(1);
 
 			at803x_context_restore(phydev, &context);
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 2df7b62c1a36811e..8f8b7747c54bc478 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -38,6 +38,7 @@
 #include <linux/phy.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>
+#include <linux/gpio/consumer.h>
 
 #include <asm/irq.h>
 
@@ -48,9 +49,26 @@
 
 int mdiobus_register_device(struct mdio_device *mdiodev)
 {
+	struct gpio_desc *gpiod = NULL;
+
 	if (mdiodev->bus->mdio_map[mdiodev->addr])
 		return -EBUSY;
 
+	/* Deassert the optional reset signal */
+	if (mdiodev->dev.of_node)
+		gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
+					       "reset-gpios", 0, GPIOD_OUT_LOW,
+					       "PHY reset");
+	if (PTR_ERR(gpiod) == -ENOENT)
+		gpiod = NULL;
+	else if (IS_ERR(gpiod))
+		return PTR_ERR(gpiod);
+
+	mdiodev->reset = gpiod;
+
+	/* Assert the reset signal again */
+	mdio_device_reset(mdiodev, 1);
+
 	mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
 
 	return 0;
@@ -420,6 +438,9 @@ void mdiobus_unregister(struct mii_bus *bus)
 		if (!mdiodev)
 			continue;
 
+		if (mdiodev->reset)
+			gpiod_put(mdiodev->reset);
+
 		mdiodev->device_remove(mdiodev);
 		mdiodev->device_free(mdiodev);
 	}
diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c
index e24f28924af8953d..75d97dd9fb281704 100644
--- a/drivers/net/phy/mdio_device.c
+++ b/drivers/net/phy/mdio_device.c
@@ -12,6 +12,8 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/errno.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -114,6 +116,13 @@ void mdio_device_remove(struct mdio_device *mdiodev)
 }
 EXPORT_SYMBOL(mdio_device_remove);
 
+void mdio_device_reset(struct mdio_device *mdiodev, int value)
+{
+	if (mdiodev->reset)
+		gpiod_set_value(mdiodev->reset, value);
+}
+EXPORT_SYMBOL(mdio_device_reset);
+
 /**
  * mdio_probe - probe an MDIO device
  * @dev: device to probe
@@ -128,8 +137,16 @@ static int mdio_probe(struct device *dev)
 	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
 	int err = 0;
 
-	if (mdiodrv->probe)
+	if (mdiodrv->probe) {
+		/* Deassert the reset signal */
+		mdio_device_reset(mdiodev, 0);
+
 		err = mdiodrv->probe(mdiodev);
+		if (err) {
+			/* Assert the reset signal */
+			mdio_device_reset(mdiodev, 1);
+		}
+	}
 
 	return err;
 }
@@ -140,9 +157,13 @@ static int mdio_remove(struct device *dev)
 	struct device_driver *drv = mdiodev->dev.driver;
 	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
 
-	if (mdiodrv->remove)
+	if (mdiodrv->remove) {
 		mdiodrv->remove(mdiodev);
 
+		/* Assert the reset signal */
+		mdio_device_reset(mdiodev, 1);
+	}
+
 	return 0;
 }
 
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 8154fb706751e8ad..1de5e242b8b4cda3 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -632,6 +632,9 @@ int phy_device_register(struct phy_device *phydev)
 	if (err)
 		return err;
 
+	/* Deassert the reset signal */
+	phy_device_reset(phydev, 0);
+
 	/* Run all of the fixups for this PHY */
 	err = phy_scan_fixups(phydev);
 	if (err) {
@@ -650,6 +653,9 @@ int phy_device_register(struct phy_device *phydev)
 	return 0;
 
  out:
+	/* Assert the reset signal */
+	phy_device_reset(phydev, 1);
+
 	mdiobus_unregister_device(&phydev->mdio);
 	return err;
 }
@@ -666,6 +672,10 @@ EXPORT_SYMBOL(phy_device_register);
 void phy_device_remove(struct phy_device *phydev)
 {
 	device_del(&phydev->mdio.dev);
+
+	/* Assert the reset signal */
+	phy_device_reset(phydev, 1);
+
 	mdiobus_unregister_device(&phydev->mdio);
 }
 EXPORT_SYMBOL(phy_device_remove);
@@ -849,6 +859,9 @@ int phy_init_hw(struct phy_device *phydev)
 {
 	int ret = 0;
 
+	/* Deassert the reset signal */
+	phy_device_reset(phydev, 0);
+
 	if (!phydev->drv || !phydev->drv->config_init)
 		return 0;
 
@@ -1126,6 +1139,9 @@ void phy_detach(struct phy_device *phydev)
 	put_device(&phydev->mdio.dev);
 	if (ndev_owner != bus->owner)
 		module_put(bus->owner);
+
+	/* Assert the reset signal */
+	phy_device_reset(phydev, 1);
 }
 EXPORT_SYMBOL(phy_detach);
 
@@ -1811,8 +1827,16 @@ static int phy_probe(struct device *dev)
 	/* Set the state to READY by default */
 	phydev->state = PHY_READY;
 
-	if (phydev->drv->probe)
+	if (phydev->drv->probe) {
+		/* Deassert the reset signal */
+		phy_device_reset(phydev, 0);
+
 		err = phydev->drv->probe(phydev);
+		if (err) {
+			/* Assert the reset signal */
+			phy_device_reset(phydev, 1);
+		}
+	}
 
 	mutex_unlock(&phydev->lock);
 
@@ -1829,8 +1853,12 @@ static int phy_remove(struct device *dev)
 	phydev->state = PHY_DOWN;
 	mutex_unlock(&phydev->lock);
 
-	if (phydev->drv && phydev->drv->remove)
+	if (phydev->drv && phydev->drv->remove) {
 		phydev->drv->remove(phydev);
+
+		/* Assert the reset signal */
+		phy_device_reset(phydev, 1);
+	}
 	phydev->drv = NULL;
 
 	return 0;
diff --git a/include/linux/mdio.h b/include/linux/mdio.h
index ca08ab16ecdc9b78..92d4e55ffe675637 100644
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -12,6 +12,7 @@
 #include <uapi/linux/mdio.h>
 #include <linux/mod_devicetable.h>
 
+struct gpio_desc;
 struct mii_bus;
 
 /* Multiple levels of nesting are possible. However typically this is
@@ -39,6 +40,7 @@ struct mdio_device {
 	/* Bus address of the MDIO device (0-31) */
 	int addr;
 	int flags;
+	struct gpio_desc *reset;
 };
 #define to_mdio_device(d) container_of(d, struct mdio_device, dev)
 
@@ -71,6 +73,7 @@ void mdio_device_free(struct mdio_device *mdiodev);
 struct mdio_device *mdio_device_create(struct mii_bus *bus, int addr);
 int mdio_device_register(struct mdio_device *mdiodev);
 void mdio_device_remove(struct mdio_device *mdiodev);
+void mdio_device_reset(struct mdio_device *mdiodev, int value);
 int mdio_driver_register(struct mdio_driver *drv);
 void mdio_driver_unregister(struct mdio_driver *drv);
 int mdio_device_bus_match(struct device *dev, struct device_driver *drv);
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 4962af37722ac2ea..6106ed915841c97e 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -841,6 +841,11 @@ int phy_aneg_done(struct phy_device *phydev);
 int phy_stop_interrupts(struct phy_device *phydev);
 int phy_restart_aneg(struct phy_device *phydev);
 
+static inline void phy_device_reset(struct phy_device *phydev, int value)
+{
+	mdio_device_reset(&phydev->mdio, value);
+}
+
 #define phydev_err(_phydev, format, args...)	\
 	dev_err(&_phydev->mdio.dev, format, ##args)
 
-- 
2.7.4

Re: [PATCH v4.1] phylib: Add device reset GPIO support

From: Richard Leitner <richard.leitner@skidata.com>
Date: 2017-12-04 16:20:20 

On 12/04/2017 01:35 PM, Geert Uytterhoeven wrote:
From: Sergei Shtylyov <redacted>

The PHY devices sometimes do have their reset signal (maybe even power
supply?) tied to some GPIO and sometimes it also does happen that a boot
loader does not leave it deasserted. So far this issue has been attacked
from (as I believe) a wrong angle: by teaching the MAC driver to manipulate
the GPIO in question; that solution, when applied to the device trees, led
to adding the PHY reset GPIO properties to the MAC device node, with one
exception: Cadence MACB driver which could handle the "reset-gpios" prop
in a PHY device subnode. I believe that the correct approach is to teach
the 'phylib' to get the MDIO device reset GPIO from the device tree node
corresponding to this device -- which this patch is doing...

Note that I had to modify the AT803x PHY driver as it would stop working
otherwise -- it made use of the reset GPIO for its own purposes...

Signed-off-by: Sergei Shtylyov <redacted>
Acked-by: Rob Herring <robh@kernel.org>
[geert: Propagate actual errors from fwnode_get_named_gpiod()]
[geert: Avoid destroying initial setup]
[geert: Consolidate GPIO descriptor acquiring code]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
Successfully tested this patch on a i.MX6SOLO based board containing a
LAN8710 PHY:

Tested-by: Richard Leitner <richard.leitner@skidata.com>

Re: [PATCH v4 0/4] Teach phylib hard-resetting devices

From: David Miller <davem@davemloft.net>
Date: 2017-12-05 17:51:58 

From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Mon,  4 Dec 2017 11:34:48 +0100

This patch series adds optional PHY reset support to phylib.
Patch #1 and #2 applied to net-next, using v4.1 of patch #1.

Thanks.

Re: [PATCH v4.1] phylib: Add device reset GPIO support

From: Sergei Shtylyov <hidden>
Date: 2017-12-07 17:20:14 

Hello!

On 12/04/2017 03:35 PM, Geert Uytterhoeven wrote:

From: Sergei Shtylyov <redacted>

The PHY devices sometimes do have their reset signal (maybe even power
supply?) tied to some GPIO and sometimes it also does happen that a boot
loader does not leave it deasserted. So far this issue has been attacked
from (as I believe) a wrong angle: by teaching the MAC driver to manipulate
the GPIO in question; that solution, when applied to the device trees, led
to adding the PHY reset GPIO properties to the MAC device node, with one
exception: Cadence MACB driver which could handle the "reset-gpios" prop
in a PHY device subnode. I believe that the correct approach is to teach
the 'phylib' to get the MDIO device reset GPIO from the device tree node
corresponding to this device -- which this patch is doing...

Note that I had to modify the AT803x PHY driver as it would stop working
otherwise -- it made use of the reset GPIO for its own purposes...

Signed-off-by: Sergei Shtylyov <redacted>
Acked-by: Rob Herring <robh@kernel.org>
[geert: Propagate actual errors from fwnode_get_named_gpiod()]
[geert: Avoid destroying initial setup]
[geert: Consolidate GPIO descriptor acquiring code]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
[...]
quoted hunk
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 2df7b62c1a36811e..8f8b7747c54bc478 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
[...]
quoted hunk
@@ -48,9 +49,26 @@
  
  int mdiobus_register_device(struct mdio_device *mdiodev)
  {
+	struct gpio_desc *gpiod = NULL;
+
  	if (mdiodev->bus->mdio_map[mdiodev->addr])
  		return -EBUSY;
  
+	/* Deassert the optional reset signal */
   Umm, but why deassert it here for such a short time?
quoted hunk
+	if (mdiodev->dev.of_node)
+		gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
+					       "reset-gpios", 0, GPIOD_OUT_LOW,
+					       "PHY reset");
+	if (PTR_ERR(gpiod) == -ENOENT)
+		gpiod = NULL;
+	else if (IS_ERR(gpiod))
+		return PTR_ERR(gpiod);
   Hm, returning on error with reset deasserted?
quoted hunk
+
+	mdiodev->reset = gpiod;
+
+	/* Assert the reset signal again */
+	mdio_device_reset(mdiodev, 1);
+
  	mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
  
  	return 0;
[...]

MBR, Sergei

Re: [PATCH v4.1] phylib: Add device reset GPIO support

From: Sergei Shtylyov <hidden>
Date: 2017-12-07 17:40:48 

On 12/07/2017 08:20 PM, Sergei Shtylyov wrote:
quoted
The PHY devices sometimes do have their reset signal (maybe even power
supply?) tied to some GPIO and sometimes it also does happen that a boot
loader does not leave it deasserted. So far this issue has been attacked
from (as I believe) a wrong angle: by teaching the MAC driver to manipulate
the GPIO in question; that solution, when applied to the device trees, led
to adding the PHY reset GPIO properties to the MAC device node, with one
exception: Cadence MACB driver which could handle the "reset-gpios" prop
in a PHY device subnode. I believe that the correct approach is to teach
the 'phylib' to get the MDIO device reset GPIO from the device tree node
corresponding to this device -- which this patch is doing...

Note that I had to modify the AT803x PHY driver as it would stop working
otherwise -- it made use of the reset GPIO for its own purposes...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org>
Acked-by: Rob Herring <redacted>
[geert: Propagate actual errors from fwnode_get_named_gpiod()]
[geert: Avoid destroying initial setup]
[geert: Consolidate GPIO descriptor acquiring code]
Signed-off-by: Geert Uytterhoeven <redacted>
[...]
quoted
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 2df7b62c1a36811e..8f8b7747c54bc478 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
[...]
quoted
@@ -48,9 +49,26 @@
  int mdiobus_register_device(struct mdio_device *mdiodev)
  {
+    struct gpio_desc *gpiod = NULL;
+
      if (mdiodev->bus->mdio_map[mdiodev->addr])
          return -EBUSY;
+    /* Deassert the optional reset signal */
    Umm, but why deassert it here for such a short time?
quoted
+    if (mdiodev->dev.of_node)
+        gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
+                           "reset-gpios", 0, GPIOD_OUT_LOW,
+                           "PHY reset");
+    if (PTR_ERR(gpiod) == -ENOENT)
+        gpiod = NULL;
+    else if (IS_ERR(gpiod))
+        return PTR_ERR(gpiod);
    Hm, returning on error with reset deasserted?
   Oops, error means we couldn't drive the GPIO at all...
   The 1st question remains though...

[...]

MBR, Sergei
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Re: [PATCH v4.1] phylib: Add device reset GPIO support

From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2017-12-08 09:55:54 

Hi Sergei,

On Thu, Dec 7, 2017 at 6:20 PM, Sergei Shtylyov
[off-list ref] wrote:
On 12/04/2017 03:35 PM, Geert Uytterhoeven wrote:
quoted
From: Sergei Shtylyov <redacted>
The PHY devices sometimes do have their reset signal (maybe even power
supply?) tied to some GPIO and sometimes it also does happen that a boot
loader does not leave it deasserted. So far this issue has been attacked
from (as I believe) a wrong angle: by teaching the MAC driver to
manipulate
the GPIO in question; that solution, when applied to the device trees, led
to adding the PHY reset GPIO properties to the MAC device node, with one
exception: Cadence MACB driver which could handle the "reset-gpios" prop
in a PHY device subnode. I believe that the correct approach is to teach
the 'phylib' to get the MDIO device reset GPIO from the device tree node
corresponding to this device -- which this patch is doing...

Note that I had to modify the AT803x PHY driver as it would stop working
otherwise -- it made use of the reset GPIO for its own purposes...

Signed-off-by: Sergei Shtylyov <redacted>
Acked-by: Rob Herring <robh@kernel.org>
[geert: Propagate actual errors from fwnode_get_named_gpiod()]
[geert: Avoid destroying initial setup]
[geert: Consolidate GPIO descriptor acquiring code]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
[...]
quoted
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 2df7b62c1a36811e..8f8b7747c54bc478 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
[...]
quoted
@@ -48,9 +49,26 @@
    int mdiobus_register_device(struct mdio_device *mdiodev)
  {
+       struct gpio_desc *gpiod = NULL;
+
        if (mdiodev->bus->mdio_map[mdiodev->addr])
                return -EBUSY;
  +     /* Deassert the optional reset signal */

   Umm, but why deassert it here for such a short time?
That's a consequence of moving it from drivers/of/of_mdio.c to here.
Not that it was deasserted that much longer in drivers/of/of_mdio.c, though...

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds





  

    
Re: [PATCH v4.1] phylib: Add device reset GPIO support

    

      From: Sergei Shtylyov <hidden>

      Date: 2017-12-08 17:20:18 
    

  

  
Hello!

On 12/08/2017 12:53 PM, Geert Uytterhoeven wrote:

quoted
On 12/04/2017 03:35 PM, Geert Uytterhoeven wrote:
quoted
From: Sergei Shtylyov <sergei.shtylyov-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org>
The PHY devices sometimes do have their reset signal (maybe even power
supply?) tied to some GPIO and sometimes it also does happen that a boot
loader does not leave it deasserted. So far this issue has been attacked
from (as I believe) a wrong angle: by teaching the MAC driver to
manipulate
the GPIO in question; that solution, when applied to the device trees, led
to adding the PHY reset GPIO properties to the MAC device node, with one
exception: Cadence MACB driver which could handle the "reset-gpios" prop
in a PHY device subnode. I believe that the correct approach is to teach
the 'phylib' to get the MDIO device reset GPIO from the device tree node
corresponding to this device -- which this patch is doing...

Note that I had to modify the AT803x PHY driver as it would stop working
otherwise -- it made use of the reset GPIO for its own purposes...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org>
Acked-by: Rob Herring <redacted>
[geert: Propagate actual errors from fwnode_get_named_gpiod()]
[geert: Avoid destroying initial setup]
[geert: Consolidate GPIO descriptor acquiring code]
Signed-off-by: Geert Uytterhoeven <redacted>
[...]
quoted
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 2df7b62c1a36811e..8f8b7747c54bc478 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
[...]
quoted
@@ -48,9 +49,26 @@
     int mdiobus_register_device(struct mdio_device *mdiodev)
   {
+       struct gpio_desc *gpiod = NULL;
+
         if (mdiodev->bus->mdio_map[mdiodev->addr])
                 return -EBUSY;
   +     /* Deassert the optional reset signal */

    Umm, but why deassert it here for such a short time?
That's a consequence of moving it from drivers/of/of_mdio.c to here.
   Well, you shouldn't do code moves without some thinking. ;-)

Not that it was deasserted that much longer in drivers/of/of_mdio.c, though...
   There it had a reason, here I'm not seeing one. Perhaps using GPIOD_ASIS (or GPIOD_OUT_HIGH) instead of GPIOD_OUT_LOW and dropping mdio_device_reset(mdiodev, 1) afterwards would make more sense here?

Gr{oetje,eeting}s,

                         Geert
MBR, Sergei
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Re: [PATCH v4 0/4] Teach phylib hard-resetting devices

    

      From: Simon Horman <horms@verge.net.au>

      Date: 2017-12-11 07:04:56 
    

  

  
On Mon, Dec 04, 2017 at 11:34:48AM +0100, Geert Uytterhoeven wrote:
	Hi David, Andrew, Florian, Simon, Magnus,

This patch series adds optional PHY reset support to phylib.

The first two patches are destined for David's net-next tree. They add
core PHY reset code, and update a driver that currently uses its own
reset code.

The last two patches are destined for Simon's renesas tree.  They add
properties to describe the EthernetAVB PHY reset topology to the common
Salvator-X/XS and ULCB DTS files, which solves two issues:
  1. On Salvator-XS, the enable pin of the regulator providing PHY power
     is connected to PRESETn, and PSCI powers down the SoC during system
     suspend.  Hence a PHY reset is needed to restore network
     functionality after system resume.
  2. Linux should not rely on the boot loader having reset the PHY, but
     should reset the PHY during driver probe.
Thanks, I have applied patches 3/4 and 4/4 for v4.16.




    
  

  
    

      

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